Staged release of ivc filter legs

ABSTRACT

A catheter for stage-delivering a vena cava filter within a body lumen is disclosed. The catheter may comprise an elongated tubular member having a proximal section, a distal section, and an inner lumen configured to receive an intravascular filter. One or more notches or slits radially disposed about the distal end of the catheter may be utilized to stage-deploy the filter within the body. Several grooves or indentations disposed along an inner surface of the catheter may also be employed.

FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of vena cavafilters. More specifically, the present invention pertains to devicesfor delivering vena cava filters within the body.

BACKGROUND OF THE INVENTION

[0002] Vena cava filters are typically used in combination with otherthrombolytic agents to treat pulmonary embolism occurring within apatient. These devices are generally implanted within a vessel such asthe inferior vena cava, and function by capturing blood clots (emboli)contained in the blood stream before they can reach the lungs and causepermanent damage to the patient. To trap emboli contained within theblood, many conventional vena cava filters utilize a plurality ofindependent filter legs that can be expanded within the body to form aconical-shaped surface that captures blood clots without disturbing theflow of blood. Once collected, a natural clot lysing process occurswithin the body to dissolve the blood clots collected by the filter.

[0003] Delivery of the vena cava filter within the body is generallyaccomplished via an introducer catheter or sheath percutaneouslyinserted through the femoral (groin) or jugular (neck) veins. Suchintroducer catheters or sheaths are generally tubular in shape, andinclude an inner lumen configured to transport the filter in a collapsedposition through the body. Once transported to a desired location in thebody (e.g. the inferior vena cava), the filter can then be removed fromwithin the catheter or sheath, allowing the filter legs to spring openand engage the vessel wall. A hook, barb or other piercing meansdisposed on the base of each filter leg can be used to secure the filterto the vessel wall.

[0004] The efficacy of vena cava filters is dependent on severalfactors, including the dimensions of the vena cava, and the alignment ofthe filter legs when the device is launched within the body. Since manyintroducer catheters deploy the filter legs simultaneously in a singlestep, the spring force resulting from the deployment of the filter legswithin the vessel may cause the filter to displace from its intendedplacement position. In some cases, the hooks on the ends of the filterlegs may also interfere with each other, causing the filter toasymmetrically deploy within the body.

SUMMARY OF THE INVENTION

[0005] The present invention relates to devices for delivering vena cavafilters within the body. In an exemplary embodiment of the presentinvention, a delivery catheter may comprise a proximal section, a distalsection, and an inner lumen configured to receive a vena cava filter.The vena cava filter may include an apical head coupled to a pluralityof expandable filter legs. Each filter leg may include a bend regionthat allows the filter to bend or flex when radially unconstrained, anda hook region to fix the filter to the vessel wall. A push memberslidably disposed within the inner lumen of the catheter can be used toeject the filter from the catheter.

[0006] One or more notches or slits radially disposed about the distalend of the catheter may be utilized to stage-deploy the vena cava filterwithin the body. The notches or slits may be formed at differing depthsand at various locations about the distal end of the catheter, dependingon the type of vena cava filter employed. In one exemplary embodiment, afirst and second set of opposing notches or slits may be formed aboutthe distal end of the catheter. The second set of opposing notches orslits may be formed adjacent to and at a depth greater than the firstset of notches or slits, forming a crenellated surface about the distalend of the catheter. In use, the push member can be used to eject thefilter legs in various stages.

[0007] In certain embodiments, the catheter may further include one ormore grooves or indentations formed along the inner surface of thedistal section. The grooves or indentations are radially aligned witheach of the notches or slits, and are configured to slidably receive thehook region on each filter leg. In use, the grooves or indentationsensure proper radial alignment of the filter legs within the innerlumen, and prevent leg crossing as the filter legs eject from thecatheter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a partial cross-sectional view of the distal portion ofa catheter in accordance with an exemplary embodiment of the presentinvention, wherein a vena cava filter is shown fully loaded within thecatheter;

[0009]FIG. 2 is a perspective view of the catheter illustrated in FIG.1;

[0010]FIG. 3 is a cross-sectional view of the catheter illustrated inFIG. 2 along line 3-3, showing the location of the grooves orindentations within the inner surface of the distal section;

[0011]FIG. 4 is a perspective view of the catheter illustrated in FIG.1, wherein the filter legs are shown withdrawn slightly from the distalend of the catheter;

[0012]FIG. 5 is a perspective view of the catheter illustrated in FIG.1, wherein the vena cava filter is shown in a second position with afirst set of filter legs ejected from the catheter; and

[0013]FIG. 6 is a perspective view of the catheter illustrated in FIG.1, wherein the vena cava filter is shown in a third position with asecond set of filter legs ejected from the catheter.

DETAILED DESCRIPTION OF THE INVENTION

[0014] The following description should be read with reference to thedrawings, in which like elements in different drawings are numbered inlike fashion. The drawings, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. Although examples of construction, dimensions, and materialsare illustrated for the various elements, those skilled in the art willrecognize that many of the examples provided have suitable alternativesthat may be utilized.

[0015]FIG. 1 is a partial cross-sectional view of the distal section ofa catheter 10 in accordance with an exemplary embodiment of the presentinvention, showing a vena cava filter 12 fully loaded within thecatheter. Catheter 10 is formed of an elongated tubular member 14 havinga proximal section 16 and a distal section 18. In the particular viewillustrated in FIG. 1, the distal section 18 of catheter 10 is shownadvanced to a desired location within a vessel V, such as the inferiorvena cava.

[0016] The proximal section 16 of catheter 10 is formed from an axiallystiff, radially flexible hypodermic tube having a proximal end (notshown) and a distal end 20. The proximal section 16 defines an innerlumen 22 configured to slidably receive a push member 24 that can bemanipulated by the physician at the proximal end of the catheter 10 toeject the filter 12 from the catheter 10 and into the vessel V. The pushmember 24 comprises an axially stiff, radially flexible tubular memberformed of a suitable metal or polymeric material with an annular-shapeddisk 26 formed at the distal end thereof.

[0017] The distal section 18 of catheter 10 is formed of a stainlesssteel hypodermic tube 14 having a proximal end 28, a distal end 30, andan inner lumen 32 configured to contain the filter 12 in a collapsedposition. The proximal end 28 of distal section 18 is attached to thedistal end 20 of the proximal section 16 at joint 34. Attachment of theproximal end 28 of the distal section 18 to the distal end 20 of theproximal section 16 can be accomplished by any number of suitablejoining methods, including adhesion bonding, ultrasonic welding, rfwelding, crimping, soldering, brazing, or any combination thereof.

[0018] The proximal and distal sections 16, 18 are dimensioned such thatthe profile of the catheter 10 is substantially uniform along the entirelength of the catheter 10. A lubricious (e.g. hydrophilic) coating maybe placed on the outer surface 36 of the catheter 10 to facilitateinsertion and advancement of the catheter 10 within the vessel V.Moreover, the inner surface 38 of the distal section 18 may be polished,buffed, or deburred to provide a smoothly bored surface to reduce thefrictional force exerted on the filter 12 by the catheter 10 whenejected from the inner lumen 32.

[0019] As shown in FIG. 1, vena cava filter 12 includes a plurality offilter legs 40 coupled to an apical head 42. Each of the filter legs 40may include a radially extending hook region 42 comprising a hook, barbor other piercing means formed on the proximal end of each filter leg40. Moreover, each of the filter legs 40 may include one or more bendregions 44 that impart flexibility to the filter 12. In the particularposition depicted in FIG. 1, the filter legs 40 are shown fully loadedwithin the inner lumen 32 such that the hook regions 42 are disposed ator near the proximal end 28 of the distal section 18. The remainder ofthe filter 12 extends distally along the length of the distal section 18with a portion extending beyond the distal end 30.

[0020] The annular-shaped disk 26 on the distal end of the push member24 acts as a proximal stop for the filter 12 when loaded into the distalsection 18 of the catheter 10, and is configured to engage the hookregions 42 when filter 12 is deployed within vessel V. Theannular-shaped disk 26 has an outer diameter that is slightly smallerthan the inner diameter of the elongated tubular member 14, allowing thedisk 26 to be advanced between the proximal and distal ends 28, 30 ofthe distal section 18. A shoulder 46 on the proximal end 28 of thedistal section 18 confines the annular-shaped disk 26 proximally.

[0021] In the exemplary embodiment illustrated in FIG. 1, filter 12 isfront-loaded into the distal section 18 of catheter 10 such that theapical head 42 portion of the filter 12 extends distally beyond thedistal end 30, and the hook region 42 of each filter leg 40 lie flushwith the annular-shaped disk 26. In a front-loaded position, filter 12can be inserted and delivered percutaneously through a femoral arterylocated near the patient's groin. The apical head 42 may have a profilesubstantially similar to the profile of the catheter 10, and may includea rounded, atraumatic distal portion 48. As with the outer surface 36 ofcatheter 10, the apical head 42 may be formed of or coated with alubricious material. The apical head 42 and/or filter legs 40 may alsobe coated with an antithrombogenic agent such as heparin (or itsderivatives), urokinase, or PPack (dextrophenylalanine proline argininechloromethylketone), if desired.

[0022] In an alternative embodiment, filter 12 can be back-loaded intothe distal section 18 of catheter 10 to permit placement of the filter12 via a jugular approach (i.e. through the jugular vein). Apical head42 can be dimensioned to slidably fit within the inner lumen 32 ofdistal section 18. To back-load the filter 12 into the catheter 10, theapical head 42 is first inserted into inner lumen 32, followed by thefilter legs 40 and hook regions 42. The distal section 18 can bedimensioned such that, when filter 12 is fully loaded into inner lumen32, the hook regions 42 do not extend beyond the distal end 30 of thecatheter 10. In use, the catheter 10 and enclosed filter 12 can beinserted percutaneously into the jugular vein, and advanced to a desiredlocation within the body. The push member 24 can then be actuated toeject the filter legs 40 from inner lumen 32. Ejection of the filterlegs 40 from the inner lumen 32 causes the filter legs 40 to expand andengage the vessel wall.

[0023]FIG. 2 is a perspective view of the catheter 10 illustrated inFIG. 1, wherein the filter 12 has been removed to show two sets ofnotches or slits 50, 52 formed at the distal end 30 of the distalsection 18. The first set of notches or slits 50 are formed by removinga portion of the elongated tubular member 14 at the distal end 30. Thefirst set of notches or slits 50 may be radially spaced 180° apart fromeach other in an opposing manner. The second set of notches or slits 52are likewise formed by removing another portion of the elongated tubularmember 14 at the distal end 30, but at a greater depth such that thesecond set of notches or slits 52 extend proximal the first set ofnotches or slits 50. As can be seen from FIG. 1, the first and secondset of notches 50, 52 extend proximally from the distal end 30 of thecatheter 10, and are located adjacent to each other to form acrenellated surface.

[0024] Catheter 10 may further include several grooves or indentations54 formed in the inner surface 38 of the elongated tubular member 14. Asshown in FIG. 3, for example, six grooves or indentations 54 may beformed at equidistant intervals about the inner surface 38 of theelongated tubular member 14. The grooves or indentations 48 extenddistally along the length of the elongated tubular member 14 from theshoulder 46 to the distal end 28, and are radially aligned with each ofthe notches or slits 50, 52. The grooves or indentations 54 areconfigured to slidably receive the hook region 42 on each filter leg 40.In use, the grooves or indentations 54 ensure proper radial alignment ofthe filter legs 40 within the inner lumen 32, and prevent leg crossingas the filter legs 40 are ejected from the catheter 10.

[0025] Referring now to FIGS. 4-6, a method of stage-deploying anintravascular filter from a catheter will now be described in thecontext of the vena cava filter 12 and catheter 10 described above. In afirst position shown in FIG. 4, catheter 10 has been withdrawn slightlysuch that the filter legs 40 are partially removed from within the innerlumen 32. Withdrawal of the filter 12 from within lumen 32 can beaccomplished by retracting the elongated tubular member 14 proximallywhile holding the push member 24 stationary, or in the alternative,holding the elongated tubular member 14 stationary while advancing thepush member 24 distally. A radiopaque marker band or other measuringmeans (not shown) may be placed on the catheter 10 and/or filter 12 todetermine the precise location of the filter 12 within the vessel.

[0026] As the operator continues to withdraw the filter 12 from thecatheter 10, the hook regions 42 a, 42 b on a first set of filter legs40 a, 40 b radially aligned with the second set of notches or slits 52eject from the inner lumen 32, allowing the filter legs 40 a, 40 b toexpand, as shown in FIG. 5. Once expanded, the hook regions 42 a, 42 bon the first set of filter legs 40 a, 40 b lock onto the vessel wall,fixing the location of the filter 12 within the vessel. Continuedretraction of the catheter 10 proximally to a second position causes asecond set of filter legs 40 c, 40 d aligned with the first set ofnotches or slits 50 to eject from the inner lumen 32, allowing thesecond set of filter legs 40 c, 40 d to expand and engage the vesselwall, as shown in FIG. 6. Further retraction of the catheter 10proximally to a third position causes the third and final set of filterlegs to eject from the inner lumen 32 and expand in like fashion. Bystage-deploying the filter legs 40 from the catheter 10, the operatorcan lock the filter 12 to a particular location along the vessel wallprior to full fixation of the device within the vessel.

[0027] The number and alignment of the notches or slits disposed aboutthe catheter can be selected to accommodate different types ofintravascular devices. For example, a catheter in accordance with anexemplary embodiment of the present invention may include eight notchesor slits radially disposed at various depths and angles about the distalend of the catheter. In use, the catheter can be utilized tostage-deploy an intravascular device (e.g. a vena cava filter) havingeight filter legs, similar to that described above with respect to FIGS.4-6.

[0028] Although FIGS. 4-6 shows the stage-deployment of a vena cavafilter having three sets of opposing filter legs, it should beunderstood that other configurations are possible without deviating fromthe scope of the invention. The catheter may be adapted to deploy eachfilter leg independently at each stage, or multiple filter legs at eachstage. For example, a catheter adapted to stage-deploy an intravascularfilter may include a group of three notches or slits radially spaced120° apart from each other. An intravascular filter having two sets ofthree filter legs radially disposed 120° apart from each other may bestage-deployed in a two-step process wherein a first group of threefilter legs are first ejected through a notched portion on the catheter,followed by the remaining filter legs from the distal end of thecatheter.

[0029] Having thus described the several embodiments of the presentinvention, those of skill in the art will readily appreciate that otherembodiments may be made and used which fall within the scope of theclaims attached hereto. Numerous advantages of the invention covered bythis document have been set forth in the foregoing description. It willbe understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size and arrangement of parts without exceeding the scope of theinvention.

What is claimed is:
 1. A catheter, comprising: an elongated tubularmember having a proximal section, a distal section, and an inner lumen;an intravascular filter disposed within the lumen; and one or morenotches or slits radially disposed about the distal end of said distalsection.
 2. The catheter of claim 1, wherein said one or more notches orslits are radially disposed at equidistant intervals about the distalend of said distal section.
 3. The catheter of claim 1, wherein said oneor more notches or slits are formed at differing depths about the distalend of said distal section.
 4. The catheter of claim 1, wherein said oneor more notches or slits comprise two sets of opposing notches.
 5. Thecatheter of claim 1, wherein said intravascular filter is a vena cavafilter.
 6. The catheter of claim 5, wherein said vena cava filter isfront-loaded into the catheter for placement through a femoral artery.7. The catheter of claim 5, wherein said vena cava filter is back-loadedinto the catheter for placement through the jugular vein.
 8. Thecatheter of claim 5, wherein said vena cava filter includes a pluralityof expandable filter legs coupled to an apical head.
 9. The catheter ofclaim 8, wherein each of said plurality of expandable filter legsincludes a hook region.
 10. The catheter of claim 1, further comprisingone or more grooves or indentations formed along an inner surface of thedistal section.
 11. The catheter of claim 10, wherein each of the one ormore grooves or indentations is radially aligned with a correspondingone of the one or more notches or slits.
 12. The catheter of claim 10,wherein said one or more grooves or indentations correspond in numberand arrangement with said one or more notches.
 13. A catheter,comprising: an elongated tubular member having a proximal section, adistal section, and an inner lumen configured to receive a vena cavafilter therein; one or more notches or slits radially disposed about thedistal end of said distal section; and one or more groves orindentations formed along an inner surface of said distal section. 14.The catheter of claim 13, wherein said catheter is configured to permitstage-deployment of the vena cava filter within a body lumen.
 15. Thecatheter of claim 13, wherein said one or more notches or slits areradially disposed at equidistant intervals about the distal end of saiddistal section.
 16. The catheter of claim 13, wherein said one or morenotches or slits are formed at differing depths about the distal end ofsaid distal section.
 17. The catheter of claim 13, wherein said one ormore notches or slits comprise two sets of opposing notches.
 18. Thecatheter of claim 13, wherein said vena cava filter is front-loaded intothe catheter for placement through a femoral artery.
 19. The catheter ofclaim 13, wherein said vena cava filter is back-loaded into the catheterfor placement through the jugular vein.
 20. The catheter of claim 13,wherein said vena cava filter includes a plurality of expandable filterlegs coupled to an apical head.
 21. The catheter of claim 20, whereineach of said plurality of expandable filter legs includes a hook region.22. The catheter of claim 13, wherein each of the one or more grooves orindentations is radially aligned with a corresponding one of the one ormore notches or slits.
 23. The catheter of claim 13, wherein said one ormore grooves or indentations correspond in number with said one or morenotches.
 24. A catheter, comprising: an elongated tubular member havinga proximal section, a distal section, and an inner lumen configured toreceive a vena cava filter therein, said vena cava filter comprising aplurality of expandable filter legs each having a hook region; one ormore notches or slits radially disposed at equidistant intervals aboutthe distal end of said distal section; and one or more groves orindentations formed along an inner surface of said distal section, saidone or more grooves or indentations configured to slidably receive acorresponding hook region on each of said plurality of filter legs;wherein the catheter is configured to permit stage-deployment of thevena cava filter within a body lumen.
 25. The catheter of claim 24,wherein said one or more notches or slits are formed at differing depthsabout the distal end of said distal section.
 26. The catheter of claim24, wherein said one or more notches or slits comprise two sets ofopposing notches.
 27. The catheter of claim 24, wherein said vena cavafilter is front-loaded into the catheter for placement through a femoralartery.
 28. The catheter of claim 24, wherein said vena cava filter isback-loaded into the catheter for placement through the jugular vein.29. The catheter of claim 24, wherein each of the one or more grooves orindentations is radially aligned with a corresponding one of the one ormore notches or slits.
 30. The catheter of claim 24, wherein said one ormore grooves or indentations correspond in number with said one or morenotches.
 31. A method of stage-deploying a vena cava filter within abody lumen, comprising the steps of: providing a catheter having aproximal section, a distal section, and an inner lumen, said catheterincluding one or more notches or slits radially disposed about thedistal end of said distal section; loading a vena cava filter into theinner lumen of said catheter, said vena cava filter having a pluralityof expandable filter legs; inserting the catheter into a body lumen;positioning the distal section of the catheter at a desired locationwithin the body; and stage-deploying the vena cava filter within saidbody lumen.
 32. A method of stage-deploying a vena cava filter within abody lumen, comprising the steps of: providing a catheter having aproximal section, a distal section, and an inner lumen, said catheterincluding one or more notches or slits radially disposed about thedistal end of said distal section; loading a vena cava filter into theinner lumen of said catheter, said vena cava filter having a pluralityof expandable filter legs; inserting the catheter into a body lumen;positioning the distal section of the catheter at a desired locationwithin the body; withdrawing the catheter to a first position, wherein afirst set of filter legs is deployed; and withdrawing the catheter to asecond position, wherein a second set of filter legs is deployed.